The D2525P family of DFB laser modules is designed to be used with a lithium niobate external modulator (see Table 5). The laser module features a polariza-tion-maintaining fiber (PMF) pigtail, enabling it to be directly connected to a modulator without the need of a polarization controller. The PMF maintains the polar-ization of the output light to a consistent orientation. This allows the D2525P to be used as a CW light source for systems requiring extremely low chirp such as undersea or 10 Gb/s systems. The module contains a multiquantum-well (MQW), distributed-feedback (DFB) laser. This device nominally has an output power of 10 mW. The wavelength of the laser can be temperature-tuned for more precise wavelength selec-tion by adjusting the temperature of the internal ther-moelectric cooler.

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The 1.5 µm D2525P Laser Module is available in a 14-pin, hermetic, butterfly package.

Wavelength-Selected D2525P

Data Sheet, Rev. 2

Isolated DFB Laser Module with PMF

February 2003

22

For additional information and latest specifications, see our website: www.triquint.com

Description

(continued)

Controlled Feedback

The module contains an internal optical isolator that sup-presses optical feedback in laser-based, fiber-optic sys-tems. Light reflected back to the laser is attenuated a minimum of 30 dB.

Controlled Temperature

An integral thermoelectric cooler (TEC) provides stable thermal characteristics. The TEC allows for heating and cooling of the laser chip to maintain a temperature of 25 °C for case temperatures from ­40 °C to +70 °C. The laser temperature is monitored by the internal thermistor, which can be used with external circuitry to control the laser chip temperature.

Controlled Power

An internal, InGaAs, PIN photodiode functions as the back-facet monitor. The photodiode monitors emission from the rear facet of the laser and, when used in conjunction with control circuitry, can control optical power launched into the fiber. Normally, this configuration is used in a feedback arrangement to maintain consistent laser output power.

Standard Package

The laser module is fabricated in a 14-pin, hermetic, metal/ceramic butterfly package that incorporates a bias tee that separates the dc-bias path from the RF input. The RF input has a nominal 25

impedance.

The laser module is equipped with Fujikura* polarization-maintaining fiber (PMF). The fiber is PANDA type and is the same fiber that is used on the TriQuint lithium niobate mod-ulators. It has a mode field diameter of 10.5

µm, a cladding

diameter of 125

µm ±3 µm, and a loose tube jacketed fiber

900

µm in diameter. The pigtail is terminated with an ST

®

ferrule

. Figure 1 shows the orientation of polarization in the

fiber.

TriQuint optoelectronic components are being qualified to rigorous internal standards that are consistent with Telcor-dia Technologies

TR-NWT-000468. All design and manu-

facturing operations are ISO

§

9001 certified. The module is

being fully qualified for central office applications.

* Fujikura is a registered trademark of Fujikura Ltd. The ST ferrule key is not aligned to slow axis of fiber. Connector is

intended for testing purposes only.

Telcordia Technologies is a trademark of Telcordia Technologies

Inc.

§ ISO is a registered trademark of The International Organization for

Standardization.

Figure 1. Polarization-Maintaining Fiber

Pin Information

1. A positive current through the thermoelectric heat pump cools the

laser.

2. Both leads should be grounded for optimum performance.

Figure 2. Circuit Schematic

Table 1. Pin Descriptions

Pin Name

1 Thermistor2

Thermistor

3

Laser dc Bias (Cathode) (­)

4

Back-facet Monitor Anode (­)

5

Back-facet Monitor Cathode (+)

6

Thermoelectric Cooler (+)

1

7

Thermoelectric Cooler (­)

1

8

Case Ground

9

Case Ground

10

Case Ground

11

Laser Anode (+)

2

12

RF Laser Input Cathode (­)

13

Laser Anode (+)

2

14

Case Ground

CORE

STRESS ROD

PRINCIPLE POLARIZATION

AXIS

CLADDINGINNER COATING

OUTER COATING

(SILICON & ACRYLATE)

1-567

Top view.

1-567

TEC

L1

160 nH

ISOLATOR

R120

PACKAGE

GROUNDS

­

+

+

­

­

+

­

+

7

6

5

4

3

2

1

8

9

10

11

12

13

TH

10 k

14

1-567.b

Data Sheet, Rev. 2

Wavelength-Selected D2525P

February 2003

Isolated DFB Laser Module with PMF

For additional information and latest specifications, see our website: www.triquint.com

3

Absolute Maximum Ratings

Stresses in excess of the absolute maximum ratings can cause permanent damage to the device. These are abso-lute stress ratings only. Functional operation of the device is not implied at these or any other conditions in excess of those given in the operations sections of the data sheet. Exposure to absolute maximum ratings for extended periods can adversely affect device reliability.

* Does not apply to shipping container.

Parameter

Symbol

Min

Max

Unit

Laser Reverse Voltage

V

RLMAX

--

2

V

dc Forward Current

I

FLMAX

--

225

mA

Operating Case Temperature Range

T

C

­40

70

°C

Storage Case Temperature Range*

T

stg

­40

70

°C

Photodiode Reverse Voltage

V

RPDMAX

--

10

V

Photodiode Forward Current

I

FPDMAX

--

2

mA

Handling Precautions

Power Sequencing

To avoid the possibility of damage to the laser module from power supply switching transients, follow thisturn-on sequence:

1. All ground connections

2. Most negative supply

3. Most positive supply

4. All remaining connections

Reverse the order for the proper turn-off sequence.

Electrostatic Discharge

CAUTION: This device is susceptible to damage as

a result of electrostatic discharge. Take proper precautions during both han-dling and testing. Follow guidelines such as JEDEC Publication No. 108-A (Dec. 1988).

TriQuint employs a human-body model (HBM) for ESD-susceptibility testing and protection-design evaluation. ESD voltage thresholds are dependent on the critical parameters used to define the model. A standard HBM (resistance = 1.5 k

, capacitance = 100 pF) is widely

used and, therefore, can be used for comparison pur-poses.

Mounting Instructions

The minimum fiber bend radius is 1.0 in.(25.4 mm)

To avoid degradation in performance, mount the mod-ule on the board as follows: